James Ashby's lawyer has sought leave to appeal against a Federal Court judgment that was highly critical of his actions in bringing a sexual harassment case against Peter Slipper.

Michael Harmer of Harmers Workplace Lawyers says the judgment has affected his professional reputation and exposed him to the potential for disciplinary action.

Justice Steven Rares last month dismissed a sexual harassment claim brought against Mr Slipper by his former staff member Mr Ashby, declaring its main purpose was to cause political damage to the former speaker.

In his judgment, Justice Rares criticised Mr Harmer's inclusion of "scandalous and irrelevant" references to suggestions that Mr Slipper had a sexual relationship with a male staff member in 2003 and that it had been recorded on video.

"The 2003 allegations had nothing to do with Mr Ashby's complaint that Mr Slipper sexually harassed him," Justice Rares wrote, declaring the purpose of its inclusion was to attract significant adverse publicity in the media.

"I am of the opinion that Mr Ashby's and [Mr Harmer's] pleading of 2003 allegations was scandalous, oppressive and vexatious and an abuse of Mr Harmer's professional obligations to the court as a lawyer."

Mr Ashby last week sought leave to appeal against the decision and yesterday his lawyer followed suit with his own application.

In documents filed with the Federal Court, Mr Harmer argues: "[Justice Rares] erred in finding that Mr Harmer intended to cause harm to Mr Slipper by including scandalous and irrelevant allegations."

He says "substantial injustice" would be done if the court does not allow the appeal, given it contains "serious adverse findings impacting upon the professional reputation and standing of Mr Harmer".

Mr Harmer says his ability to give evidence was limited by his legal and professional obligations because of Mr Ashby's claims for "client legal privilege", adding that he was never cross-examined in relation to the allegations.

He says the case has highlighted important questions about the professional obligations on solicitors when filing originating applications or pleadings in the court.

A court hearing for Mr Harmer's application for leave to appeal is due to be heard on February 6 at the same time as Mr Ashby's application.